**Show Us Your Installs!!!**

[Spudnik]

Right chaps,

Due to a few unavoidable issues, we have lost the original thread and pics etc.

Sorry about that!!!

So, if you want to re-upload your pics then great, if not, give us something new!


Cheers!!

 

[ChrisElectrical88]

Yep, this is a standard requirement for sub-station rooms/buildings. Never, ever seen this done in aluminium though. That is possibly going to create more problems than it's initial cost reduction!!

Normally the two ends of this room loop would connect to a MET/MET earth bar, with removable links to facilitate testing. One section of the earth bar would connect all the earthing conductors, such as earth rods, Ufer earth mat, etc, and a second section would contain electrical links from cables TX, switch boards etc. The tape would be used to locally connect and equalise other metal structures or componants within the room, like the metal doors, windows (if any) ventilation louvers and other metallic plant, like AC units and/or it's ducting etc....

We're hoping to have a few more of these of the back of this then doing them quite regular if everything goes ok. Will be interesting to see if the other ones we do are aluminium or copper tapes.

 

[Engineer54]

We're hoping to have a few more of these of the back of this then doing them quite regular if everything goes ok. Will be interesting to see if the other ones we do are aluminium or copper tapes.

Well you won't be able to fabricate bends around the doors etc, as you have done in this case with aluminium. You'll have to use copper tape fittings similar to that used in lightning protection systems.

To be honest, i really can't see why they have specified Aluminium tape, i can see all sorts of problems arising in the future, high resistance joints being just one of them, caused by corrosion/degradation of the aluminium, especially where any dissimilar metals are involved. I'm just wondering if they will install a Copper earth bar separate from this equipotential tape for all the other electrical earthing connections and connecting your tape to that, via a linking conductor?? Who knows, certainly not how i would have specified this installation anyway!! lol!! Copper rules in substations, and for very good reasons!!

 

[Outspoken]

I have to agree with E54 here, I have completed installs in numerous primary and secondary subs over the years and have only ever used Cu tape, never Al.

For me one of the issues is that they are clearly relying on atmospheric Oxygen to react with the tape to create a protective coating of AlO[SUB]2,[/SUB] and this raises all kinds of potential issues at joints because if any of the Oxide gets into the joints the risk not only of a galvanic reaction[SUB],[/SUB] butthe impedance of the joint could become a serious issue as AlO[SUB]2[/SUB] is non-conductive and can cause serious degradation of the joint....hence all joints need to be 100% and they need to be protected with a non-conductive, non-reactive substance, such as grease or petroleum jelly.

Aluminium is horrible stuff for electrical work!!

 

[Knobhead]

Look at the DNO’s current specifications for substations. Aluminium is permitted for earthing.

Not saying I like it, but it’s permitted.

 

[Engineer54]

Look at the DNO’s current specifications for substations. Aluminium is permitted for earthing.

Not saying I like it, but it’s permitted.

It wouldn't surprise me at all Tony!! It seems like everywhere else in the UK, the accountants are taking over Engineering decisions!! This could be yet another mistake, very much like the use of 3 1/2 core cables in the past, to save a bit of money on they're extensive LV network installations.... Only time will tell if the use of Al on sub station earthing will also come back and bite them hard on the arse!! ...lol!!

 

[Knobhead]

I’ll hold my hand up, I must have run miles of 3½C.

Things like VSD and SMPS were weird and wonderful things then. You only had to worry about the 3[SUP]rd[/SUP] natural harmonic in the neutral.

There was a lot to be said for our old 550V system, no neutral!

 

[ChrisElectrical88]

Intresting to read your thoughts on this. Scottish Power have met one of our lads on site today and signed off the work and he is happy with it. It looks like we will have a few more of these stating soon so ill keep you up to date with what is specified to be installed in those ones. Ill raise the question about why its not copper tape as well.

 

[Knobhead]

Would be interesting to hear the answer. The spec I’ve got allows both CU and Al. without trawling through them I cant remember the sizes.

I’ve got to talk to UKPN soon, will ask the question.

 

[Guest55]

a minor update of my on-going project with additional pics.......

before.....



after......



before.....



after......



before , new & old submains......



after a tidy up......



before ........



after , nothing left other than the main earthing i managed to salvage.....
all bonds labelled , E54 will be so proud lol ;-)




most difficult tray run .......



only 2 anchor points along the whole run to the plant below , so most of it free standing , quite pleased with that really.

 

[specs]

They’ve been using it since I were a lad.

I went to EMEB’s training collage about 30 years back. They had us jointing Al to Cu 11KV cables.

I remember, in the early seventies, buying aluminium cored t&e, can't remember the 'why' but I do remember it went on for about 6 months or maybe a year. Anybody care to jog my memory.

 

[Phoenix]

I remember, in the early seventies, buying aluminium cored t&e, can't remember the 'why' but I do remember it went on for about 6 months or maybe a year. Anybody care to jog my memory.

I think that was down to rocketing copper prices and availability. Was it not copper coated? Bit blurry thinking that far back...

 

[Engineer54]

Yep, copper coated Al cable in T&E form. Required 4mm for 30A ring circuits and 1.5mm for 5A lighting circuits!!
As far as i know still available, but only in 16mm and above sizes!!

 

[ipf]

Marketed as 'copperclad'. Waste of time for various reasons.

 

[Knobhead]

Never come across Cu coated Al. Sounds horrible stuff!

The cables I was referring to were 11KV 185mm² Al PILCSWA joined to 11KV 70mm² Cu PILCSWA. You have to bind the Cu conductor with 2.5mm² until it’s the same size as the larger conductor and then sweat it solid. It’s a ball ache!

 

[ipf]

Never come across Cu coated Al. Sounds horrible stuff!

The cables I was referring to were 11KV 185mm² Al PILCSWA joined to 11KV 70mm² Cu PILCSWA. You have to bind the Cu conductor with 2.5mm² until it’s the same size as the larger conductor and then sweat it solid. It’s a ball ache!

Been as well terminating that 4mm CCA in the same way. The stuff WAS horrible...and those terms were like mush. Normal screw terms went straight through it. I think it was MK who made a special range with flat to flat connection points especially for it.